1. Field of the Invention
The present invention relates to the generation and isolation of flavinogenic strains of Candida famata for the production of riboflavin.
Riboflavin, most commonly known as vitamin B.sub.2, an enzyme cofactor is found to some degree in virtually all naturally occurring foods. It is widely used in pharmaceuticals, food-enrichment, and feed supplements.
Riboflavin has been commercially produced by fermentation. Most commercially produced riboflavin is consumed as a crude concentrate for enriching animal feed. Riboflavin also finds use for human consumption. The present invention is concerned with the development of Candida famata strains for the efficient and economic production of riboflavin.
2. Brief Description of the Relevant Literature
Varieties of Candida yeasts are attractive as flavinogenic organisms because they grow rapidly on a simple, well known medium. P. R. Burkholder, Proc. Nat. Acad. Sci., U.S.A., (1943) 29:166.
Candida famata has been studied for a number of years for its flavinogenic capacities. See, e.g., Enari and Kauppinen, Acta. Chem. Scand. (1961) 15:1513. In particular, the inhibitory effect of iron and trace elements on riboflavin production has been investigated. Tanner et al., Science (1945) 101:180. So far, riboflavin production by C. famata has proven to be variable. Early pilot plant fermentations using simple non-sterilized culture mediums gave riboflavin yields of 325 mg/liter. Levine, H., et al., Industrial and Engineering Chemistry (1949) 41:1665.
Certain varieties of Candida yeasts have been known to produce substantial amounts of riboflavin. For example, a modification employing Candida intermedia var A, a newly isolated microorganism assimilating lactose and ethanol, has ben disclosed in Japanese Patent No. 73/19,958 and yields reported of 49.2 mg riboflavin per liter. Candida T-3 also produces riboflavin from methanol, as disclosed in Japanese Patent No. 76/19,187. See also, EPA 0 137 226 for disclosure of Candida robusta for riboflavin production.